I've found that they're not all created equal and E85 is just nuts in the GTR's

Extremely true........kind of reminds me of the N54 scene, you can run two 335's with similar bolt ons and race gas and the results will be different.....all dependent on how aggressively they are tuned! some of these e85 gtr's are ticking time bombs.....I know the one I raced blew up 3 weeks later